As the design of vehicles, automobiles and small trucks in particular, has evolved, headlights have continually been reconfigured to improve the aerodynamics of the front end of the vehicle. Modern headlights are designed so that their lenses follow the contour of the vehicle to provide an aerodynamically efficient exterior surface. However, adjustment of these headlights must still be performed in order to provide an optimal beam of light and to prevent the aiming of light beams toward oncoming vehicles. Automotive manufacturers' demand for aerodynamically efficient headlight designs has led to modular designs requiring the headlight adjustment mechanism to be located within the interior of the engine compartment so that adjustment can be easily performed without removing any trim pieces. Thus, the constraints of the installation area and the demands of the automobile manufacturers for aerodynamic headlight designs dictate that an adjuster for use with the aerodynamic designs be adjustable from inside the engine compartment using ordinary tools, and must be able to translate rotational motion of the adjusting part into linear motion of the adjusting means that adjusts the lamp within the headlight assembly. There are many devices incorporating such designs including, among others, the devices disclosed in U.S. Pat. Nos. 5,707,133; 5,214,971; and 6,257,747 to Burton, the inventor of the present invention, the disclosures of which are incorporated herein by reference.
Automotive lamp assemblies used as headlights typically include several basic parts: a support frame, a reflector, a lens, a bulb, and one or more adjusters. The support frame either completely houses the reflector and the bulb on a pivotable mounting to allow the aim of the light to be adjusted using the adjusters or provides a mounting surface for attaching a headlamp adjuster. The lens seals the front of either the support frame or directly to the reflector to protect it from the elements assailing the front end of the vehicle and provides an aerodynamic shape and attractive appearance. The reflector mounts on one fixed ball joint and is adjustable horizontally and vertically using adjusters that interface with the reflector through moving ball joints. The moving ball joints are moveable by actuating the adjusters connected to the moving ball joints by a ball stud having a head and a shaft. Right angle style adjusters, such as the ones disclosed in some of the Burton patents referenced above, are often used to allow the adjustment of the headlight from an adjusting position above the installed headlight. In other applications, motorized adjusters, straight adjusters, or other types of adjuster are used. In addition to the adjustability of the lamp assemblies, due to the significant amount of vibration experienced during operation of the vehicle, it is important for the adjuster to retain its set position.